1. Field of the Invention
The present invention relates to utility systems and, more specifically, to a prefabricated segmented system for building bio-retention system enclosures.
2. Description of the Prior Art
Storm water runoff places a substantial economic burden on public water treatment facilities. As open land comes under development and is paved over, storm water that would otherwise be absorbed by soil flows into local storm sewer systems. Such water often suspends solids and other pollutants as it flows over paved surfaces. Once in the storm sewer system, the water flows to a water treatment facility where it must be treated to remove the solids and pollutants. Not only is such water treatment expensive, but so is the cost of infrastructure improvements necessary to convey the storm water.
Local bio-retention basins are increasingly used to catch storm water and allow it to settle solids locally before transfer to a storm sewer system. Many such basins also allow storm water to be infiltrated into the surrounding soil, thereby reducing the demands placed on the local storm sewer system.
A bio-retention system can be configured as a rain garden. A rain garden is a garden that diverts storm water for storm water filtration and groundwater recharge. Typically, a rain garden includes an area that retains storm water that would otherwise flow into the storm sewer system. Rain gardens mitigate the effects of runoff in urban areas by allowing storm water to seep into the water table, thereby filtering the water by the surface soil and preventing flow of the storm water into the storm sewer system. Also, some rain gardens use storm water to grow aesthetically pleasing plants, thereby making urban areas more attractive. Use of rain gardens in medians and next to sidewalks that would otherwise be paved over results in less stress on the municipality's drainage systems, improved groundwater quality and a more pleasing urban environment.
Most bio-retention basins include a surrounding curb or retaining wall used to form an enclosure that keeps water local to the basin. Water inlets are included to allow water to flow into the basin and water outlets are provided to allow overflow to exit the basin.
Unfortunately, in an urban environment, construction of bio-retention basins can be difficult to construct and expensive. One method of constructing such a basin includes setting concrete forms in the configuration of the basin, placing concrete in the forms, allowing the concrete to cure, removing the forms and then placing gravel and soil in the basin. This method is costly, labor intensive and may be difficult to perform in a limited urban environment.
Another method includes pre-casting an entire unitary retention system designed to fit into a specific site. The unitary system is then transported to the site on a truck and then installed. Such a unitary system can be bulky and costly to transport. This method may also be difficult to use in limited urban environments and it is inflexible because once installed, it cannot be easily modified.
Therefore, there is a need for a segmental bio-retention enclosure system that is prefabricated, easily transported, inexpensive and that can be arranged in various layouts to accommodate given site conditions.